Crown block shifting apparatus and method

ABSTRACT

A drilling rig derrick is adapted to direct the hoist lines reeved between the crown block and the traveling block such that they enter both in a vertical direction if the traveling block is moved laterally to clear the work area over the rotary table. Arrangements are provided to move the crown block laterally, and to move it back over the rotary table. Alternate provisions displace the reeved lines with idler sheaves to move the traveling block only and direct the reeved lines such that they enter both crown block and traveling block sheaves in a near vertical direction. Methods for both options are provided.

[0001] This invention pertains to the main hoisting system of a drilling rig derrick. More specifically, but not in a limiting sense, it pertains to means to move the traveling block suspension lines laterally to suspend the traveling block some lateral distance from the work area over the rotary table.

BACKGROUND OF INVENTION

[0002] By conventional practice, the traveling block of the main hoisting system of a drilling rig has been employed in most vertical movement of the pipe string. An assembled pipe string may weigh in the order of five hundred tons and that is appropriate use of the main hoisting system. The main system, however, has been used to handle single sections of pipe. New pipe sections are within the weight handling capacity of secondary lifting gear. Lighter handling means were not usable in the past, to add pipe sections to the pipe string, because the traveling block occupied the traffic path above the rotary table.

[0003] The assembled pipe string was supported, along the well center line, in a spider near the derrick floor. The traveling block was moved upward in the derrick, lifting the new section to a position for its lower end to be connected to the pipe string in the spider. The large lifting system was involved in handling a light weight load. That was inefficient use of massive and slow hoisting equipment.

[0004] New systems have been installed to handle the pipe section while the slower traveling block is being raised to address the top of the new section. Activities related to connecting the new section to the pipe string can be underway while the traveling block is engaged in the upward excursion. When the traveling block reaches the required position, the lighter section handling gear is moved away to allow the traveling block to lower the pipe string. The enabling factor has been side shifting arrangements to pull the traveling block toward the side of the derrick to clear the well centerline above the rotary table for the new section handling gear. The side shifting system is trolley-mounted to accommodate the upwardly moving traveling block. Under those displaced conditions the traveling block is not used to lift significant loads.

[0005] Early drilling rigs were used such that the draw works was opposite the vee door, giving the driller the best possible view of activities. When the traveling block was used to lift loads entering the vee door it was practical to orient the crown block with the sheave axes transverse to the vee door, parallel to the axis of the cable drum, so that displacement of the traveling block toward the vee door caused the least damage to reeved cables entering the crown block sheaves.

[0006] The evolution of the main hoisting gear in the derrick has resulted in some changes in the early relationships between the draw works cable drum but the changes have not been severe. Ancillary gear related to the hoist system has crowded the drilling floor such that the newly added ability to shift the traveling block, to clear the work area over the rotary table, may be done in a direction along the axis of rotation of the cable sheaves in both the crown block and traveling block. That causes the cables to be skewed when entering and leaving the sheaves if the traveling block alone is laterally displaced. The traveling block can be moved only a limited distance toward the crown block, increasing the angle of misalignment, before the cables begin to chafe unacceptably on the sheaves. In such cases the height to which the traveling block can be raised is less than that possible if the traveling block is directly below the crown block, or the lines routed to move vertically to and from both the crown block and traveling block. The difference is wasted pipe handling capacity.

[0007] The hoisting cable is wound on the cable drum of the drawworks, extends as a live line to the crown block through intermediate sheaves, is reeved about twelve times between crown block and traveling block, extends down as a dead line from the crown block, extends through a clamp, and extends on, to a reserve cable storage reel. As cable wears in the sheaves, more line is occasionally run off the reserve reel, along the routes cited above, and a length is cut off the end anchored to the draw works cable drum. Economics of the matter will not tolerate running a misaligned traveling block too near the crown block, with the resulting chafing of the cable.

[0008] The excess distance below the crown block at which the traveling block is stopped is wasted derrick space. The economics of that wasted derrick space makes the new handling system less attractive than it would be if the traveling block could be raised higher each trip. Otherwise stated, if the traveling block can be moved higher, a longer new pipe length can be added to the pipe string each trip made by the traveling block. That is economically beneficial because a rig can complete a well in less time. The rig time is expensive and the petroleum is becoming a more critical industrial necessity.

SUMMARY OF THE INVENTION

[0009] Therefore, it is an object of this invention to provide apparatus to direct the reeved suspension lines vertically into and out of the crown block and traveling block when the traveling block is laterally displaced.

[0010] It is another object of this invention to provide apparatus to move the crown block of a drilling rig laterally to suspend the traveling block to one side of the rotary table centerline to clear the work area over the rotary table to permit activity above the rotary table not requiring the traveling block.

[0011] It is yet another object to provide reeved suspension lines with side loading idler sheaves arranged to move the lines laterally, and return them to the un-displaced state to move the traveling block laterally relative to the centerline of the rotary table.

[0012] To achieve the objectives, provisions near the top of a derrick, move the crown block laterally to suspend the traveling block clear of the work area over the rotary table. It also moves the crown block back to center the traveling block over the rotary table. Otherwise stated, provisions to move the crown block laterally permits the traveling block to be raised while clear of the work area over the rotary table and moves the crown block, and traveling block, back over the rotary table to make a downward excursion with a pipe string load. Such movement allows lighter pipe handling gear to erect a stand of pipe over the pipe string suspended from a spider for connecting the new section to the pipe string while the traveling block makes its upward excursion.

[0013] If the traveling block is stabilized by means to control its upward movement when displaced laterally, the movement of the crown block keeps the sheaves in the crown block and the sheaves in the traveling block acceptably aligned to avoid chafing cables reeved about sheaves of both blocks.

[0014] Three options are disclosed for moving the traveling block laterally. One concept distorts the derrick to move the crown block laterally, and consequently moves the suspended traveling block laterally. A second concept distorts the normal path of the reeved lines between crown block and traveling block to leave the crown block in place and move the suspended traveling block. The preferred concept for lateral displacement moves the crown block laterally relative to the derrick, to move the suspended traveling block laterally. All concepts can work well with systems that force the traveling block laterally by aligning the reeved lines with the related sheaves.

[0015] In the preferred form, a shuttle carriage equipped with either skid means or roller means moves along a carriage way on the derrick to laterally transport the crown block. Movement of the shuttle is powered by force delivery means, preferably at least one hydraulic cylinder. Jack screws or gear-and-rack moving means are typical of equivalent alternatives. To assure reliable function, a combination of carriage-moving contrivances can be used.

[0016] When conditions permit, idler sheaves are situated in the derrick and arranged to move the reeved suspension lines laterally just below the crown block to displace the lines such that the traveling block is suspended a selected distance from the centerline of the rotary table. Moving the idler sheaves back to a neutral position then positions the traveling block over the rotary table centerline. Two sets of sheaves are usually needed for the lateral displacement function and they are preferably all carried on one shuttle fixture secured to the derrick. A third set of sheaves can be used to favorably route the reeved lines downward from the crown block.

[0017] Alternative arrangements distort the derrick by tilting the top of the derrick to displace the crown block relative to the rotary table. In one embodiment the top of the derrick is rigid and hinged in one side. Lifting gear, preferably hydraulic cylinders, lift the side of the derrick opposite the hinges.

[0018] A second tilting arrangement does not separate derrick legs but skews two sides of a parallelogram derrick section to displace the crown block relative to the rotary table.

[0019] These and other objects, advantages, and features of this invention will be apparent to those skilled in the art from a consideration of this specification, including the attached claims and appended drawings.

BRIEF DESCRIPTION OF DRAWINGS

[0020] In the drawings, similar captions refer to similar features.

[0021]FIG. 1 is a side view of a prior art representative derrick and associated hoisting equipment.

[0022]FIG. 2 is a side view similar to FIG. 1, also prior art, with a traveling block moved laterally to clear the work area over the rotary table.

[0023]FIG. 3 is a side view of the novel arrangement to move both crown block and the traveling block clear of the work area over the rotary table.

[0024]FIG. 4 is a side view of the novel arrangement with the crown block of FIG. 3 moved back over the rotary table.

[0025]FIG. 5 is an elevation of a crown block shifting assembly, partly cut away, viewed perpendicularly to the sheave axes.

[0026]FIG. 6 is a sectional view taken along line 6-6 of FIG. 5.

[0027]FIG. 7 is a view from the aspect of FIG. 6 but with rollers instead of skids.

[0028]FIG. 8 shows line and sheave arrangements for rerouting reeved lines.

[0029]FIG. 9 is identical to FIG. 8, with rerouting displacement of lines.

[0030]FIG. 10 is an end view of the shuttle arrangement for FIGS. 8 and 9.

[0031]FIG. 11 is identical to FIG. 9, with an extra routing sheave.

[0032]FIG. 12 is a side view of a distortable derrick.

[0033]FIG. 13 is a side view of the distortable derrick in the tilted position.

[0034]FIG. 14 is a side view of an alternate form of distortable derrick, in the straight configuration.

[0035]FIG. 15 is identical to FIG. 14, with the derrick top skewed.

DETAILED DESCRIPTION OF DRAWINGS

[0036]FIG. 1 shows representative derrick 1 supporting crown block 5 with sheaves 10 suspending traveling block 4, on upper structure 11, and elevator 3 by cables 8 reeved about sheaves 9 supporting pipe string P which extends through rotary table 2. This is prior art.

[0037]FIG. 2 has the same situation as FIG. 1, represents prior art, but the traveling block has lowered the pipe string P, now supported by spider 2. The connector, or collar, 14 is situated at a working height above base structure 15. The traveling block has been moved to one side by trolley means 12 which is capable of moving vertically along track 13. When the traveling block moves higher, the cables 8 are skewed at an increasing angle. Cables 8 are chafed by the entry and exit angles relative to sheaves 9 in the traveling block and sheaves 10 in the crown block. The lateral movement of the traveling block is done to clear the work area over the rotary table to permit manipulator 7, of varied forms and choices, to position a new section S of pipe for attachment to the pipe string suspended in the spider 2. This process is prior art and permits the positioning and connection of the new pipe section while the slow traveling block makes the upward excursion. Pipe tongs are often present near the rotary table but are not shown.

[0038]FIG. 3 shows the same derrick 1 but the crown block 5 is moved laterally by a carriage (shown in detail by FIGS. 5 and 6) which moves along a carriage way, or track, (see FIGS. 5 and 6) on the modified upper structure 11A to place the crown block over the laterally displaced traveling block.

[0039]FIG. 4 shows the crown block moved back over the rotary table to position the traveling block in alignment with the rotary table, and the pipe string centerline, in preparation for lowering the assembled pipe string into the well. Elevator 3 is not yet attached to the pipe string. Normally, the elevator will be connected to the pipe string before the manipulator 7 releases the new pipe stand S. The elevator will lift the pipe string and the spider will release the pipe string when it is supported by the elevator.

[0040] In FIGS. 5 and 6 the major derrick upper structure 11A is fitted with slideways 24 to allow the crown block mounted on skids 23 to move laterally. Movement is forced by hydraulic cylinders 21 mounted on structure 20 to act against structure 22 to move the crown block an amount set by the travel limiter 25. The space below the crown block, between cables 8, is unobstructed. At times the crown block is lowered through that opening for maintenance. The hydraulic cylinders will normally be connected to hydraulic plumbing (not shown) that lead to a power source and controls near the rig floor.

[0041]FIG. 7 is a fragmented view from the aspect of FIG. 6 but showing rollers 31 rolling inmodified track 30 on the modified crown block carriage 32. Wheels on axles are shown but commercially available and equivalent circulating rollers can carry an elongated bearing plate along the same roller way. Such load carrying contrivances are well known to those skilled in the art of machine construction.

[0042]FIG. 8 is devoid of derrick structure not needed in disclosing points of novelty. Crown block sheave 50 is carried by derrick mounted support 51. Reeved suspension lines 58 support traveling block sheave 57. That configuration leaves the hook line of movement HLM coincident with the well center line WCL. Just below the crown block, attached to the derrick, shuttle tracks 60 carry shuttle 54 which carries idler sheaves 56 and 55. The shuttle is moved laterally by hydraulic cylinder 53 which is secured to the derrick by bracket 52.

[0043] In FIG. 9, with no shuttle or tracks shown, sheaves 56 and 55 are shown to have moved the reeved lines 58 laterally to place the traveling block such that the hook moves along line HLM some distance from the well center line WCL.

[0044] Note that the portion 58 a of the reeved lines 58 depart the crown block at a large angle relative to vertical. Not all derrick geometry will accept such line configuration. The arrangement of FIG. 11 results.

[0045] In FIG. 11, idler sheave 61, supported by the derrick by way of bracket 60 minimizes the derrick section plan form area required to accept the lines. The balance of FIG. 11 is much the same as FIG. 9.

[0046]FIG. 10 is an end view of the shuttle track 60, taken along line 10-10 of FIG. 8. Tracks 60 are secured to the derrick. Shuttle 54 carries four wheels, two shown as 55 a and 55 b, which run in the channel of beams 60. Shuttle 54 also carries sheaves 55 and 56 (56 shown) which engage the reeved lines 58 to accomplish the line configuration of FIG. 9 or 10.

[0047] Well drilling sites are well known for unexpected conditions which disable peripheral hydraulic systems, and other powered apparatus. Often, it is important in such cases to have the main hoisting gear operational in the conventional manner over the well centerline. On the preferred embodiment, the roller way 24 can be constructed with an upward slope toward the right end viewed from the aspect of FIG. 5. The crown block would be level but would rise during the rightward excursion. In case of hydraulic failure when the crown block is in the rightwardly displaced position, the hydraulic system could be vented of restraining fluid and the crown block would roll to the left back to the leftward position. The rig hoisting gear could then be used in the conventional manner until the problem is corrected.

[0048] The apparatus of FIGS. 8, 9, and 11 are naturally self restoring in that they tend to return to the configuration that leaves the traveling block over the rotary table, unless they are restrained in the traveling block displacing state. The self-restoring ability is anticipated by and is within the scope of the claims.

[0049] Hydraulic shifting cylinders are currently preferred for moving the crown block but other equivalent means of forcing movement can be used. Powered lead screws and rack and pinion moving means are well established in the art of machine construction and may be used instead of hydraulic cylinders. Such construction is anticipated by and is within the scope of the claims.

[0050] It is common practice in rig operations to use cable sheaves just above the draw works to assist in level winding of cable onto the cable drum. Other guide sheaves are situated in the derrick to define the path of the dead line and to aid in control of the live, or fast, line between the cable drum and the crown block sheaves. Positioning and management of those intermediate sheaves differ with different drilling rigs. Choices of such varied arrangements are anticipated by the claims. Such choices are well established in the art of derrick rigging and their omission from the claims is not to be construed in a limiting sense. Any anticipated choices for intermediate sheave usage may be used with the apparatus of this invention.

[0051]FIGS. 12 and 13 show two upper portions 70 and 71 of a derrick having hinge line 76 along one side and power tilt means 75 on the opposite side. When the power tilt means, shown as a hydraulic cylinder, is extended, the upper portion tilts about hinge line 76 to place the crown block 72 some distance from the original position. Traveling block 73 is then suspended to move along vertical line HLM. That is some lateral distance from the original line of vertical lift WCL. If necessary, draining fluid from the cylinder 75 will cause the derrick to correct to the symmetrical arrangement of FIG. 12.

[0052]FIGS. 14 and 15 show a derrick arrangement is which portion 80 could be the derrick base structure or a higher structure in the derrick. Crown block 72, traveling block 73, lines of motion WCL and HLM, are the same as those in FIGS. 12 and 13. Lateral movement of the crown block results from skewing derrick structure rather than lifting one side. There are four hinge lines that allow sides 81 a and 82 a to tilt but remain parallel. That holds structure 84 level, or in the original attitude but moved laterally. Power skewing motor 83, preferably a pair of hydraulic cylinders, operate against side 81 a to control the skew and the skew correction. There are several possible equivalent lines of action for the skewing motor. Sides 81 a and 82 a, viewed from the side relative to the plane of the drawing, can be tapered or rectangular.

[0053] Oil field rigging art is old and well established. The apparatus of this invention will be used on derricks of many different configurations. Those skilled in the art will have no problem adapting the points of novelty presented herein to the many different derrick structures to be encountered.

[0054] From the foregoing, it will be seen that this invention is one well adapted to attain all of the ends and objects hereinabove set forth, together with other advantages which are obvious and which are inherent to the apparatus.

[0055] It will be understood that certain features and sub-combinations are of utility and may be employed without reference to other features and sub-combinations. This is contemplated by and is within the scope of the claims.

[0056] As many possible embodiments may be made of the apparatus of this invention without departing from the scope thereof, it is to be understood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense. 

The invention having been described, we claim:
 1. Apparatus for moving a crown block of a drilling rig laterally relative to the vertical centerline of the rotary table to move the suspended position of the traveling block to one side of the work area over the rotary table, the apparatus comprising: a) a distortable derrick capable of responding to an applied distorting force to move the crown block a preselected distance between a first position placing a suspended traveling block over the vertical centerline of the rotary table and a second position placing the traveling block some horizontal distance from said vertical centerline of the rotary table; b) forcing means operatively associated with said derrick to apply said distorting force.
 2. The apparatus of claim 1 wherein said derrick has one portion hinged relative to the rest of the derrick, said forcing means arranged to bend the derrick at a selected hinge line.
 3. The apparatus of claim 1 wherein said derrick consists of two portions, a first portion having a generally parallelogram structure, viewed from either of two opposite sides, with four hinge centerlines defining flexure points, said forcing means arranged to move the upper of the parallelogram structure relative it's lower end.
 4. The apparatus of claim 1 wherein said crown block is moved laterally, relative to the rest of the derrick, between said two positions.
 5. The apparatus of claim 1 wherein idler sheaves engage the reeved suspension lines between crown block and traveling block, said idler sheaves arranged to move laterally in response to said applied distorting force to move the lines such that the suspended traveling block moves laterally between the work area over the rotary table and a location some transverse distance from the vertical centerline of the rotary table.
 6. Apparatus for moving the crown block of a drilling rig between a first position, generally over the centerline of the rotary table, and a second position some distance to laterally displace the suspended traveling block, the apparatus comprising: a) a shuttle carriage to support the crown block; b) a support track mounted on the rig to support said shuttle carriage and accept movement between said two positions; and c) force means arranged to apply force to said carriage relative to said track to move said carriage between said two positions.
 7. The apparatus of claim 6 wherein said shuttle carriage has wheels arranged to roll on said support track.
 8. The apparatus of claim 6 wherein said shuttle carriage has skid pads arranged to slide on said track.
 9. The apparatus of claim 6 wherein said force means is a hydraulic cylinder.
 10. The apparatus of claim 6 wherein said force means is a jack screw and nut arrangement.
 11. The apparatus of claim 6 wherein said force means is a pinion and rack arrangement.
 12. The apparatus of claim 6 wherein said support track is sloped upward in the direction of displacement from the first position such that the carriage, when displaced, will move back to the first position in the absence of a restraining force.
 13. The apparatus of claim 6 wherein said movement of said crown block responds to control means near the rig floor.
 14. The apparatus of claim 6 wherein said shuttle carriage is incorporated into the embodiment of said crown block.
 15. Apparatus for moving the crown block of a drilling rig between a first position, generally over the centerline of the rotary table, and a second position some lateral distance to align sheaves of the crown block with the sheaves of a laterally displaced traveling block, the apparatus comprising: a) a shuttle carriage to support the crown block; b) a support track mounted on the rig to support said shuttle carriage and accept movement between said two positions; and c) force means arranged to apply force to said carriage relative to said track to move said carriage between said two positions.
 16. The apparatus of claim 15 wherein said shuttle carriage has wheels arranged to roll on said support track.
 17. The apparatus of claim 15 wherein said shuttle carriage has skid pads arranged to slide on said track.
 18. The apparatus of claim 15 wherein said force means is a hydraulic cylinder.
 19. The apparatus of claim 15 wherein said force means is a jack screw and nut arrangement.
 20. The apparatus of claim 15 wherein said force means is a pinion and rack arrangement.
 21. The apparatus of claim 15 wherein said support track is sloped upward in the direction of displacement from the first position such that the carriage, when displaced, will move back to the first position in the absence of a restraining force.
 22. The apparatus of claim 15 wherein said movement of said crown block responds to control means near the rig floor.
 23. The apparatus of claim 15 wherein said shuttle carriage is incorporated into the embodiment of said crown block.
 24. Apparatus for moving the crown block of a drilling rig between a first position, generally over the centerline of the rotary table, and a second position some lateral distance to reduce the angle, off vertical, of cables reeved between sheaves of the crown block and the sheaves of a laterally displaced traveling block, the apparatus comprising: a) a shuttle carriage arranged to support the crown block; b) a support track mounted on the rig to support said shuttle carriage and accept movement between said two positions; and c) force means to apply force between said track and said carriage to move said carriage between said two positions.
 25. The apparatus of claim 24 wherein said shuttle carriage has wheels arranged to roll on said support track.
 26. The apparatus of claim 24 wherein said shuttle carriage has skid pads arranged to slide on said track.
 27. The apparatus of claim 24 wherein said force means is a hydraulic cylinder.
 28. The apparatus of claim 24 wherein said force means is a jack screw and nut arrangement.
 29. The apparatus of claim 24 wherein said force means is a pinion and rack arrangement.
 30. The apparatus of claim 24 wherein said support track is sloped upward in the direction of displacement from the first position such that the carriage, when displaced, will move back to the first position in the absence of a restraining force.
 31. The apparatus of claim 24 wherein said movement of said crown block responds to control means near the rig floor.
 32. The apparatus of claim 24 wherein said shuttle carriage is incorporated into the embodiment of said crown block.
 33. A method for conducting pipe string assembly management operations on a drilling rig having a crown block, a traveling block, and cables reeved between crown block sheaves and traveling block sheaves, and a work area over a rotary table, the method comprising the steps: a) displacing the traveling block laterally from the work area over the rotary table; b) moving the crown block laterally to a location generally over the displaced traveling block; c) conducting pipe assembly management work over the rotary table and moving the traveling block to make an upward excursion; d) moving the crown block back over the rotary table to suspend the traveling block over the rotary table; and e) suspending the pipe string upper end from the traveling block and moving the pipe string axially through the opening of the rotary table.
 34. A method for conducting pipe string assembly management operations on a drilling rig having a crown block, a traveling block, and cables reeved between crown block sheaves and traveling block sheaves, and a work area over a rotary table, the method comprising the steps: a) displacing the crown block laterally from the work area over the rotary table to displace the traveling block laterally from the work area over the rotary table; b) conducting pipe assembly management work over the rotary table and moving the traveling block to make an upward excursion; c) moving the crown block back over the rotary table; and d) suspending the pipe string upper end from the traveling block and moving the pipe string axially through the opening of the rotary table.
 35. The method of claim 34 wherein said pipe assembly management is related to tripping the pipe string out of the hole.
 36. The method of claim 34 wherein said pipe assembly management is related to tripping the pipe string into the hole.
 37. The method of claim 34 wherein said pipe assembly management is related to tripping the pipe string out of the hole.
 38. The method of claim 34 wherein said pipe assembly management is related to tripping the pipe string into the hole. 